1. Technical Field
The present invention relates to an image processing apparatus, an image processing method, and a program for reading the front surfaces of media including portions printed with ink which produces fluorescence during irradiation with ultraviolet rays.
2. Related Art
In financial institutions, if a check is received, the check is put on a check processing apparatus, and magnetic ink characters printed on the check are magnetically read, whereby magnetic information is acquired. Then, based on the magnetic information, a clearing process is performed. Also, in financial institutions, in parallel with the reading of the magnetic ink characters, the front surface of the check irradiated with visible rays is read by the check processing apparatus, whereby an image of the front surface is acquired, and the image is kept as an evidence of the clearing. Further, in financial institutions, in a case of using a check on which there is a forgery prevention image printed with ink which produces fluorescence during irradiation with ultraviolet rays (hereinafter, referred to as UV ink), the front surface of the check irradiated with ultraviolet rays is read by a check processing apparatus, whereby an image of the front surface is acquired, and the acquired image is used to determine whether the check is genuine. Also, in financial institutions, the image of the front surface of the check irradiated with the ultraviolet rays is kept as an evidence of clearing.
A check processing apparatus usable in that check clearing process is disclosed in JP-A-2013-070225. The check processing apparatus disclosed in JP-A-2013-070225 includes a magnetic sensor for magnetically reading magnetic ink characters, and an image sensor for irradiating the front surface of a check with read light, thereby acquiring an image of the front surface. The image sensor emits visible rays and ultraviolet rays as read light. Also, according to JIS Z 8120, the lower limit of the wavelengths of electromagnetic waves corresponding to visible rays is about 360 nm to 400 nm, and rays with wavelengths shorter than those of visible rays are defined as ultraviolet rays.
The front surface of a check irradiated with ultraviolet rays is read by the image sensor, whereby an image is acquired. This image is acquired by capturing light (ultraviolet rays) reflected from the front surface of the check to the read light, and fluorescence produced by UV ink forming a forgery prevention image. Also, the acquired image is a gray scale image in which image portions acquired by capturing the light (ultraviolet rays) reflected from the front surface of the check to the read light are dark, and image portions acquired by capturing the fluorescence produced by the UV ink are bright.
Here, in a case where the concentration of UV ink forming a forgery prevention image is not sufficient, fluorescence weakens. As a result, image portions acquired by capturing the fluorescence become dark, and thus it may become difficult to verify the forgery prevention image based on an acquired image.
Also, in a case of keeping an image of the front surface of a check irradiated with visible rays and an image of the front surface of the check irradiated with ultraviolet rays as evidences of clearing based on the check, there is a problem in which the volume of data on images to be kept increases. Here, in order to suppress the volume of data on images to be kept as evidences of clearing, it can be considered to synthesize an image of the front surface of a check irradiated with visible rays and an image of the front surface of the check irradiated with ultraviolet rays into one image and keep the synthetic image.
However, in a case of simply synthesizing the two images of the front surface, some problems such as a problem in which it becomes difficult to recognize a forgery prevention image in the synthetic image occur.
An object of the present invention is to provide an image processing apparatus, an image processing method, and a program for synthesizing an image of the front surface of a medium irradiated with visible rays and an image of the front surface of the medium irradiated with ultraviolet rays such that it is easy to discriminate a portion printed with UV ink, in view of the above described points.